The market for wearable devices is fast growing and many companies and institutes are developing the devices actively. The challenge for wireless charging on wearable devices (e.g., smartwatches, smart eyewear, health monitors, medical devices, and so on) is that the devices are not generally 2-dimensional (as in a computer tablet, for example) but are typically 3-dimensional in shape. This geometric irregularity makes it beneficial to the design of power receiving elements for such devices configured for wirelessly receiving power (sometimes referred to as a power receiving unit or “PRU”) to improve or maintain sufficient mutual inductance (M) while accommodating appropriate M variation.